Luke Donald, the prize of golf’s free-agent class, has signed with Lagardère Unlimited and will be represented by Steve Loy, Phil Mickelson’s agent.

Donald, whose deal with IMG Golf expired at the end of 2013, was the world’s No. 1-ranked golfer for 55 weeks of 2011-12 before struggling through ’13.

Luke Donald was the world’s No. 1 for parts of 2011-12 but struggled in 2013.Photo by: GETTY IMAGES

Donald’s signing represents another significant boost to Lagardère’s burgeoning golf business, which also is acquiring an event business, Portland-based Jeff Sanders Promotions. Sanders’ 24-year-old company runs several Web.com Tour tournaments and works with companies to create golf outings for their customers with PGA and LPGA stars.

The acquisition is the latest move in golf by longtime sports industry executive Andy Pierce, who was hired as president and CEO of Lagardère Unlimited’s North American business last summer by Lagardère Group Chairman and CEO Arnaud Lagardère with a mandate to grow the company’s sports assets.

The acquisition of Jeff Sanders Promotions checks an important box for Lagardère as it seeks to round out its full-service global golf division. Jeff Sanders Promotions will provide Lagardère with a platform to get into the events business. Sanders will join Lagardère Unlimited as president, golf events management, and report to Loy, who is president of Lagardère Unlimited Golf.

Lagardère also has signed two other PGA Tour golfers, Jamie Lovemark and Ricky Barnes.

Donald, Barnes and Lovemark bring to 45 the number of players Lagardère represents on the PGA Tour. That’s believed to be the most of any agency by a wide margin.

“In terms of global capabilities and global assets in golf, we have more than any other agency,” Pierce said last week. “And that is by design, not default.”

Pierce indicated, as well, that this is not the end of Lagardère Unlimited’s acquisition spree.

After being hired in August, Pierce in October acquired Crown Sports Management and its stable of 25 golfers. Lagardère also brought in experienced agent Jay Danzi, who represents up-and-comer Jordan Spieth.

Pierce then hired veteran industry executive Charley Moore as a consultant to build Lagardère’s consulting practice in North America, and Irish golf executive Roddy Carr to build a consulting business in Europe and Asia.

Moore, Pierce and Danzi are all former IMG executives, and Carr was an IMG client when he was a player.

All of those moves were completed last fall, and now Donald’s signing sends the agency into 2014 with another surge of momentum.

“I think it’s fair to say, having learned the business at IMG, I saw the advantages of being dominant in golf,” Pierce said. “And we are well on our way to doing that at Lagardère.”

Donald, a globe-trotting golfer known for his busy international schedule, will immediately become one of Lagardère’s most-prized clients.

“As a global player based in the States, Lagardère Unlimited is a perfect fit for me.” Donald said in a statement. “Lagardère has golf’s top management team, tour players, and solid marketing relationships with the world’s premier brands. Lagardère has a family feel, while also having a global reach.”

Loy, who sold his business, Gaylord Sports Management, to Lagardère in 2012, said the fact that it is a global company — Lagardère Group is headquartered in Paris — was a major factor in signing Donald. “I recruited him about 10 years ago, and we didn’t have a platform to represent him in Europe and around the world, and he went with IMG,” Loy said of Donald.

Mickelson, Loy added, likes and respects Donald and approved of the move. In addition to Loy, Donald will be represented by Ben Harrison, a senior vice president for the golf division.

Donald, an Englishman who came to the U.S. and played college golf at Northwestern, has won five times on the PGA Tour. He ascended to No. 1 in the world in 2011 and stayed there for 55 weeks. During that time, he made history by becoming the first player to top the money lists for both the PGA Tour and the European Tour.

Harrison also will represent Lovemark, while Loy and Lagardère vice president Tim McNulty will represent Barnes.

Lovemark, who comes from IMG as well, played at USC and has won twice on the Web.com Tour, including once in 2013. Barnes, a 10-year pro who won the U.S. Amateur championship in 2002, was formerly represented by Blake Sports Group.

Loy said he also is excited about the addition of Jeff Sanders Promotions and what it will mean for Lagardère’s golf clients. Jeff Sanders Promotions owns or manages six golf events, including the Albertsons Boise Open on the Web.com Tour, but has been involved in managing and producing more than 250 events, including the U.S. Amateur in 1996 when Tiger Woods won his third amateur championship.

With an events business division, Lagardère can now expand into managing and producing PGA Tour and European Tour events, as well as charity and made-for-television events for its golf clients. Lagardère Unlimited has strong NFL player and tennis player representation practices, and Pierce said it was also possible that the events division could create assets in other sports.

“We have the clients, we have the capabilities, and we have the ability to create assets and content we think are relevant in today’s world,” Pierce said.